Vincent Petrarca and Katherine Hogan don't have a singular style, but they do have a distinctive vision.

Look through the portfolio of houses designed and built by the Raleigh, N.C.–based Tonic Design | Tonic Construction. While the architecture is decidedly modern in inspiration, zeroing in on a singular style isn’t easy. In the Rank Residence, completed last year, a dramatic, Gothic-inspired four-story home uses slender windows and a dizzying stair design to play off vertical space. The Smart-Stell Residence, by contrast, is a quieter, one-story, horizontal home with vast expanses of glass. Each residence presents an entirely distinctive vision, which, it turns out, is the connective tissue of Tonic.

“Look at two of our houses and they couldn’t be more different,” says Vincent Petrarca, Assoc. AIA, who co-founded Tonic a decade ago and now runs the firm with his wife and partner, Katherine Hogan, Assoc. AIA. “We are good at figuring out what each project is about and not making it about us.”

This doesn’t mean, of course, that Petrarca, 41, and Hogan, 32, don’t bring a signature sensibility to their work. What threads through every Tonic project is a reverence for material, a respect for the site and the budget, and what Hogan calls a “modern sensitivity.”

“We try to be really good listeners with our clients,” Hogan says, “and we try to involve them while also providing good design and remaining sensitive to the context.”

That context consists, by and large, of the North Carolina region where Tonic is based. In the last decade, the firm has completed more than 50 projects and has racked up a long list of major awards along the way. Several of its residences are embedded in suburban communities and surrounded by spec houses, so that stumbling onto a Tonic home amid so much factory-ready repetition feels like discovering a diamond in the rough. Their Lanning Residence, for example, sits on a tiny lot at the end of a cul-de-sac, a narrow site that developers believed unusable. Petrarca and Hogan thrive on such a challenge, in no small part because their firm is in charge of both design and construction for their projects. Much of what happens in a Tonic project happens on the jobsite.

“In architecture school, you learn architecture,” Petrarca says, “but in practice, it’s the trades that teach you what’s important. Lessons on the jobsite are what get us going. It’s our proving ground.”

Working on site and applying materials and methods in new ways is what keeps the firm inspired—so much so, in fact, that Tonic prefers the designation of “construction-led design” over design/build. “Something will happen when building,” Petrarca says, “and that lesson in that moment informs us when we’re working on the next design. At Tonic, because we make things, we always think about how something gets built when we’re coming up with a creative design.”

Jim West / JWest ProductionsWith the Cary, N.C., Lanning Residence, Hogan and Petrarca brought modern infill to a lot in a cul-de-sac that was previously thought to be unbuildable.

This hands-on approach to architecture is something that Petrarca learned while working with Frank Harmon, FAIA. Petrarca was still an undergraduate student at North Carolina State University when he first met Harmon and after graduation he worked at Harmon’s studio for 10 years. “He became like a father figure for me,” Petrarca says. “Sometimes, a project couldn’t afford certain things and we would start making pieces. We would make the doors, we made handrails, pottery. Frank was great because he allowed me to fall into this blur between design and construction.”

Harmon also threw a young Petrarca into leadership roles that allowed him to experience the jobsite. Petrarca flew to the Bahamas to oversee the construction of the Harmon-designed Taylor House, which included an upside-down pyramid roof for collecting rainwater?a feature that contributed to its win as project of the year in the 2002 Residential Architect Design Awards. Petrarca remembers talking a nervous roofing contractor through the process. Harmon remembers it, too. “The house wouldn’t have turned out as well if Vinny hadn’t been there,” Harmon says. “He helped the contractor and the owner figure out the best way to make a rather daring roof relatively simple to construct. If you’re in the field and you’ve got a problem, you couldn’t ask for a better person than Vinny to solve it.”

Petrarca left in 2003 and founded Tonic with two designers from Harmon’s studio. He says they had no real business plan at the start. “When we left Frank’s, with his blessing, we had one client and we said, ‘Let’s do the design and the build and push this one house as far as we can push it, and see how good we could be,’ ” he says.

Hogan joined Tonic in 2008, coming from a background that also embraced both design/build and a respect for client relationships. After graduating with an architecture degree from Syracuse University, she worked with Will Bruder in Phoenix. “He was incredibly talented, and amazing with materials and space. I learned a lot from him,” Hogan says.

In 2006, she took a year-long fellowship with Bryan Bell of Design Corps, the Raleigh-based nonprofit that provides design services to clients without ready access to architects. “Everyone is in need of design and architecture, but they don’t always have the opportunity to participate in that process,” Hogan says. “I believe everyone deserves to be a client.”

At Design Corps, Hogan came up with a clever housing solution for blueberry farm workers by combining a manufacturer’s prefab unit with a site-built lean-to. “She made it very easy to add on to the manufacturer’s building at the site and she doubled the size of the house,” Bell says.

Both Bell and Bruder say Hogan is astute with a sensibility and warmth that she converts into beautiful, pragmatic designs. “Most of us never sit down with a client in school, and that’s a loss for the profession because we don’t know how to listen,” Bell says. “Too many of us feel like the client interferes, but Katherine has respect for the end user regardless of budget.”

When Hogan and Petrarca met in 2007, they found kindred spirits in one another. Today, they work out of a 2,000-square-foot building known as the Bickett Studio—an abandoned structure that they adaptively reused and renovated—that contains both their offices and the 700-square-foot apartment where they live with their two young daughters. At holidays, they move the drawings and the models, stash the computers, and host friends and family around their work desk. “Being able to work and live in the same building, the kids get to see everything and we get to put them to bed—and after, we can do a little work,” Petrarca says. “That might sound crazy, but we love it.”

Bruder remembers visiting their studio a few years ago and touring their houses around Raleigh. “You have to experience their work first hand because there are just so many details and so many nuances,” he says. “Their style is not about fashion. It’s about their belief in the ability of the elements of architecture to solve problems in unique ways. They may conceive something in their studio, but, for them, architecture is a living process, not a stagnant one. They are always opportunistic.”

This opportunism, combined with their willingness to collaborate with subs in problem solving, means that many Tonic houses come in under $200 per square foot. “We’ve saved our clients lots of money by working with the trades,” Petrarca says.

For one project, Tonic chose metal roofing as siding, so they invited a roofing expert to offer thoughts on execution. “Instead of doing a lot of drawings, we said, ‘Here’s a window, this is what we want, why don’t you do a mock-up for us?’ ” Hogan says. “This approach allows us to say: ‘How would you do it?’ ”

And a decade of building relationships with subcontractors has allowed their process to evolve. “We don’t make many drawings anymore, because we make mock-ups and work with the trades. After we get the foundation plan and a few key heights, everyone knows what to do,” Petrarca says.

Todd Lanning / Gravitation StudiosFor Crabill Modern, a house in Hillsborough, N.C., Tonic took cues from agricultural buildings in the area and reinterpreted them in a structure wrapped in Cor-Ten panels and screens.

This fall, Hogan and Petrarca will add another job to their CV: teaching. Petrarca is an adjunct at N.C. State’s College of Design, where he and Hogan will co-teach a studio. “The teaching aspect is big for us, because when you’re in academia, you’re staying fresh,” Petrarca says. But they won’t just be giving tests, they are taking them too: Hogan is one exam away from becoming licensed, which is another goal for the firm.

Looking forward, they hope to expand their portfolio to include more commercial projects, like the sculptural outdoor pavilion that they built for the North Carolina Museum of Art. The perforated aluminum building has won several awards, including a 2010 AIA Small Project Award.

“What we do for our profession is our lifestyle,” Petrarca says. “We can’t really see the difference between work and living. It’s our passion, and in the last five years, we’ve really hit our stride.”

Todd Lanning / Gravitation StudiosDespite its focus on new construction, Tonic also takes on adaptive reuse projects, such as the retrofit of an abandoned commercial building in Raleigh into Bickett Studio, which houses the firm’s office and Hogan and Petrarca’s living space.

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About the Author

Elizabeth Evitts Dickinson

Elizabeth Evitts Dickinson has been a contributing editor with ARCHITECT since 2008. Her articles and essays have appeared in The New York Times, Metropolis, Fast Company's Co.Design, and The Atlantic's CityLab, among many other publications.